Lead storage battery



April 27, 1943.

H. HAEBLER LEAD STORAGE BATTER Y 4 Sheets-Sheet 1 Filed Jan. 25, 1940 7/ N, NICKEL COPPER 0R MERCURY H. HAEBLER LEAD STORAGE BATTERY April 27, 1943.

4 Sheets-Sheet 2 Filed Jan. 25, 1940 4 Sheets-Sheet s izkblb t A um/W April 27, 1943.

H. HAEBLER LEAD STORAGE BATTERY Filed Jan; 25, 1940 4 Sheets-Sheet 4 PatentedApr.27,1943 v I 2317 7594 LEAD STORAGEBATTERY I Herbert Haebler, 'stuttgart, Germany; team t e i n qon r WWW... ,Application January 25', 1940', 'Serial,No. 3 15,613

, InGermany'January'I, 1939, v V comma 7101. 136- 6 v v This invention relates to a lead storage bate particularly oi,the pulsating type, at highfin... tery having grid plates coated-with metal. tensities the negativeplates arev rundown first.

It is well, known in the art. to.cover with The invention iurtherprovides; therefore, that rubber thoseportions-of' antimoniallead grids in storage batteries intended for-dischargev at that are not coated with active material to. 5 low current intensities.withinion erpericds the prevent the loss of antimony; It is further positive grids .are coatedwith .metal and in 7 known to applyv a protectivecoating of lead diistorage batteries to be discharged at higherim oxide mixed with a plastic substance to the tensitiesin a short time or to be intermittently 5 positive plate of a lead storage battery oracdischarged at highrintensities, particularly selfcumulator or'to protect the alloy of antimonial: l starter batteries, the-negative grids only.

accumulator grids ,i'rom becomingpooriinanti- Theinventionis illustrated-: way of exammony by giving the grids a thin'coat oipure. pieinthe accompanying drawin a'in which lead, thereby preventing, also, contaminationotv Figure l is asideqviewof aiead storagebat the electrolyte of sulfuric acid by antimonycomtery;

pounds. V Fig: 2,;a fro t view or a positive plateof the The invention has forits object to providebattery; z r i 7 a lead storage battery the-electrodes of which Fig. 3, a sectionon .the line III-III, of Fig. comprise grid plates filled with active massand 2; and 1 I in whichthe positive or the'negative grid plates, Figs. 4 to.6 are dischargedia rams.

or both of them, for the purpose of increasing The storage batteryshownwin Fig. 1 comprises the capacity of the battery, ,have acoating or- "a hard rubber..-container l whichis notaflectedfl metal, except leadpthat does not dissolve in" by 'suiiuricacld and inwhich ,electrodeplates f the electrolyte of sulfuric acid. Suitable for this i are arranged inkn wn mann r, the positive purpose are all metalswhich do not dissolve plates '3 andthenegative plates .2 *formingthe 1 in. the electrolyte, as tin, nickel, copper, mer-"'2 usual sets. Each 'celllisshut'ofl ontop by 9. cury, etc., whereas zinc, for instance, which icover provided with=borings and .possessii'm. andissolves in sulfuric acid, and, surprisinelmalso opening. closable by a s o per. o pou in lead cannot be used-though the lattermetalthe acid. p w e does not dissolve in the acid. The unsuitability Asindicated in -.Figs.'- 2 and 3, each electrode of leadin this respectis particularly 'remark- '30 plate-comprises ai'raxnei fitted with alug 6,

' able in view of the fact that thisImetaI-i'nay' a small-meshed grid l andthe pas 3 0 1 17- be advantageously employed in reducing-the fins, in positive pla es; lar ly 0 l ad lf e 1loss of antimony'from the grids of lead store mixed withleadperoxide and, innegativeplates,' i1 1 age batteries. Tin, on the other hand, has been y '01 spon y l w di t0 the i v e found-to give excellent results asgcoating mefine-meshed grid I, prior tcbeing provided with dium; It'may be advisable-to coat the positive-1 the active paste, receives a metal coating 8 which. and the negative grids with difierent metals" .doesrnot dissolve in'the electrolyte. V and in one embodiment of the invention at least-"" The diagram shown in, Fig. :4 indicates the onegroup of grids is coated withlnickel applied- I influence exer ed by tinn d rl s "upon a disupon copper layer, 3 4 charge performed at a. current intensity of 7.5' c f Experiments have shown that the maximum amperes. The time. tris plotted. in hours-0n 1 increase in capacity is obtainable by coating thexabscissa and thevoltage onthe ordinates;

oniyoneoi' the groups 01' positive and negative w The curves represent conditions ascertained at, platesinstead otboth groups, this group; being the-26th discharge. frhe'points, throughwhich the one that limits the capacity. of the battery ithe'fcurvelislaid calculated mean values of by being-"run down first during discharge. 'I'he threemeasuredcellsi Thepotential of the plates positive and negative platesare not rendered wasascertain'ed by means'oias'tandard cadmium u ineffective simultaneously, and it can be readily" electrode. The diagram shown m 'Fig,L.4"is-"todetermined by test in each instance which one be read ashaving ablank' portlononiitted or of thetwo kinds of plates is rundown first. so cut away immediately abovethe figure -indi- I It is generallyknown that the capacity differs eating-the voltage -0.5.. g 3 I according to the manner of' discharging, and Referring toFim'of the drawings, the upper it has now been ascertained that slow discharge lines, at b, c, and d, indicate voltage curves of at low current intensities exhausts first the the positive' plates oifa storage battery having positive Plates whilst in case of'rapid-discharge, grids madeof theusual lead' alloy-consisting of plate having its grid tin-coated, with a negative plate also having its grid tin-coated.

' vhavirg non-tinned grids, at a discharge rat imum capacity of a lead storage battery. *Al

- tained same reference-lettersgused in Fig. 4', and the referencej letters 'e. and f designate; the voltage curve for the negative plate corresponding. to

.' voltage curve, g, indicates a the "results attained is that obtained with'an unccated grid when? used with a negative plate also having itsgrid uncoated, while the voltage curve, b, indicates the voltages obtained when a positive plate with" 5 uncoated grid is used with anegative plate hav ing its'grid coated withztin. The voltage curve, C, shows the. result obtained when using a'positive The'voltage curve it indicates the results obtainedywhen the positive plate has its 'grid tinrcoated but the negative grid-has its. grid un coated. The lower curves in Fig. eindicate the voltage.

measured at the negative plates, the voltage I v curve, e, being that obtained witha negative plate.

having a tin-coated grid, the voltage curve I."

is thatobtained with a negative plate having,

a grid which is tin-coated used with a positive; plate whose grid istin-coated;

Fig. 4 further I shows that in case of .platesi-i-" of 7.5 amperes, the positive'plate limits the max though the use of grids provided with metal coat-. ing's according to the invention does not alter this condition); there is nevertheless: an increase. in capacity which is greatest in such circumstances when the positive plate, which limits capacity, 0

. 'fis'tin-coat'ed and this is lessened. when the nega-g .tive' plate,- also,- is thus treated. If bothgrids are tin-coated, the capacity will represent a mean valueresultingfrom the individual valuesatby coating only the positive orthe l ege-" tivefgrid's'. I Fig.5 shows that at a dischargerate of 225 withthe'invention has a powerful efiect again,

uponarisein' capacity.- The reference letters,: a, b; c, and d designate the voltage curves of the "positive: plates-corresponding tothose with the those with the same. reference letters in Fig. 4.. Two additional voltage curves,-.gg and h, are shown injFig. 5, for the negative" plate. The

ata high rate of discharge, namely, 225, amperes... when'the negative platehas itsgrid coated with tin and the positiveplate hasits. grid uncoated.

- The voltage curve 71. indicates the result attained at the same high rate of discharge when using anegativelplate whose grid is ,uncoated, with a positivel plate whose grid is coated with tin.

."Inconside'ring the voltage curves,; the nature of the'linewill indicate the respective-positive andinegative voltage curves which are to be taken *together asdesignating the action of a given. battery.-,, For example, a ande, indicate one pair of voltage curves, band g another, 6

and I a third pair, and d and It: afourth pair.

The negative; plate limits capacity also in case of intermittent discharge at high intensity, which closely approaches conditions prevailing at the starting of self-starter batteries. fy

2,317,759 93% lead and 7% antimony. The voltage curved Y on the ordinate.

the--25th,discharge.

2 matter beginning with page 222. As previously stated, the potential of the plateswas ascer- Fig. 6 shows the results of experiments made with plates comprising non-tinned and tincoated grids at intermittent discharge. The

curves are distinguished in the manner'made use ,of in Figs. 4 and 5. During the experiments covered by Fig. 6 the discharge was carried out at 260 amperes ior.13 seconds, then interrupted for 2 'minutes, resumed again at 260 amperes for 13 seconds, and so forth. The number of pulsations 1!. is shown on the abscissa and the voltage I The curves were plotted at As indicated. by the curves of Fig. 6, coatinz of the grids of electrode platesaccording to the invention affords in this instance surpassing advantages consisting'in very considerable increases in capacity.- In this diagram a blankv portionis omitted between the horizontal axis and the voltage line 0.2 and also a blank portion is omitted'between the voltage lines 1.4 and 2.

The voltage curves of the positive and negative plates as set out in Figs. 4-6 were obtained in accordance with the standard procedure outlined, for example, in the publication entitled Storage Battery" by George Wood Vinal (1930), see'the tained by means of-a standard cadmium electrodeandthe index or symbol Cd (cadmiuml'on the voltage curves in these figures is used'to indicate this.- Inmeasuring the potential, the voltmeter islconnected between the positive (or negative) plate of the-lead storage battery and the standard cadmium electrode, which latter is introduced into the electrolyte of the battery before the measurement-begins. The difference betweenthevoltage of the positive plates and that of the negative plates gives the practical voltage of the battery.

Themetal coats may crationgor preferably. by plating, the thickness of the applied layer of metal being not of decisive importance.- The layers are preferably of moderate thickness soflas to prevent any material increase in the self-discharge of the bat-- teries, but they must atle'ast firmly adhere'to the grids. If nickel isjused for coating, firm adhesion 'to a lead grid may be insured for instance by'employing an intermediate layerof The materials for the gridslmay comprise the usualgrid alloys. 1. 7

The experimental results illustrated show that the increase 'in' capacity attained by coating the r'ids with metal becomes particularly apparent whenyvery, high discharge currents are'taken from thebattery ashappens for instance in a case. of self starter batteries. The rapid .ex-

haustionoi a battery w'as. hitherto generally ascribed to the lowering of thesulfuric acid concentration and/orthe sintering of the negative mass, but theefiects obtained by the application of the invention make it appear probable. that the reductions of the capacity occurring in the course of time in a storage battery are largely due to a resistance, a sort of insulating coating, which forms gradually. It remains undecided whether this formation of an insulating coating is identical with the phenomenon known as -sulfating. The metalcoatings of the grid plates produce a well conducting surface and thus probably counteract the formation of a capacitydiminishihgq-insul atin'g layer. Furthermore, they reduce'the charging voltage and increase the be applied to the grids by immersion, hot galvanizing, spraying, evap-.

voltage on discharge. The life of a set of storage batteries constructed according to the invention is longer than that of a set of batteries of known ,type. The slight increase in self-discharge which might occur due to the provision of the grids 5 with metal coatings remains within tolerable limits.

The rise in capacity produced according to the invention could be ascertained also'at low temperatures, as 10 to -15 C.

Iclaim: p 1. In a storage battery of the lead-acid type, having grids of metal selected from the group consisting of lead, and lead-alloy, filled with ac- 1 tive mass to form storage battery grid plates, a group of grid plates each having the entire surface of its grid covered with an outer coating of tin.

2. In a storage battery of the lead-acid type, having grids of metal selected from the group consisting of lead, and lead-alloy, filled with active mass to form storage battery grid plates,

.a. group of positive grid plates each having the entire surface of its grid covered with an outer coating of tin.

3. In a storage battery of. the lead-acid type, 7

having grids of metal selected from the/group consisting of lead, and lead-alloy, filled with active mass to form storage battery grid plates, 8. group of negative grid plates eachhaving the 5 entire surface of its'grid coveredwith an outer coating of tin.

HERBERT HAEBLER. 

